This report outlines the findings of a study performed to establish the respirable dust generation characteristics of a number of mining activities. A series of thirty-eight tests were performed on five mines in order to establish the respirable dust generation rates linked to activities presumed to be hazardous in this respect. The aim of this study was to identify prominent dust sources that occur in hard rock mines and to characterise these by means of on-site measurement of dust generations. The activities identified for the studies were drilling, scraping, tipping, crushing and rock transfer. The study indicates that dust generation rates are activity dependent and that geological areas contribute to the silica content of the dust.